Properties that vary with temperature enable thermometry

Steps:

• Recall that thermometers use physical properties changing predictably with temperature.
• Check option A: length expands in metals via thermal expansion coefficient.
• Check option B: mass stays constant, unaffected by temperature.
• Check options C and D: pressure and resistance increase with temperature per gas laws and resistivity formulas.

Why B is correct:

• Mass is conserved and invariant to temperature changes, per the principle of mass conservation in closed systems, unlike expansible properties.

Why the others are wrong:

• A: Length of metal bars increases with temperature due to linear thermal expansion (ΔL = αLΔT).
• C: Gas pressure rises with temperature at constant volume (Gay-Lussac's law: P ∝ T).
• D: Wire resistance grows with temperature (R = R₀(1 + αΔT)).

Final answer: B